Chabazite+Thom+Wair

Spectrum Details

Modality

FTIR

Category

soil

Material Type

Intimate

Sample ID

HS193

Collection Locality

Colorado

Spectral Purity

1b2b3b4_ # 1= 0.2-3, 2= 1.5-6, 3= 6-25, 4= 20-150 microns

Composition / XRD

None # XRF, EPMA, ICP(Trace), WChem

Sample Description

Chabazite is usually found in rhombohedral crystals, with nearly cubic angles. The ideal composition listed in the FORMULA field often has considerable replacement of Ca by Na and K as well as (Na,K)Si for CaAl. The structure of chabazite consists of an Al-Si-O framework with large cage like openings bounded by rings of tetrahedra. The cages are connected to each other by channels which allow diffusion of molecules of less than ~3.9 Angstroms. The bands seen in its near-infrared spectrum are typical of large quantities of molecular water. See: Hunt, G.R., J.W. Salisbury, 1970, Visible and near-infrared spectra of minerals and rocks: I. Silicate minerals. Modern Geology, v. 1, p. 283-300.

XRD Analysis

40 kV - 30 mA, 6.5-9.5 keV File: chab193.out, -.mdi; chabz193.out, -.mdi References: JCPDS # 34-137, 35-498, 42-1451 Found: Chabazite, thomasite (thomsonite?), wairaikite in sub equal proportions Comment: Reflections are sharp and strong, suggesting good crystallinity and compositional homogeneity. Many peak overlaps made interpretation of the pattern very difficult. Consideration of the relative intensities of chabazite and thomasite led to the realization that some sharp peak had an intensity contribution from a third phase, which turned out to be wairaikite. J.S.Huebner, J. Pickrell, T. Schaefer, written communication(USGS 1994)

X Units

cm⁻¹

Y Units

Absorbance

Data Points

1,801